Tire construction



Feb. 1 ,1921.

`1,616,069 J. C. TUTTLE ET AL. l

` TIRE CONSTRUCTION Original Filed March 2 1920 Fig.

inventors. Jahn Cffute John Fmh Martin L .Wienev by mty.

Patented Feb. 1, ,1927.

UNITED sil-auras PATENT OFFICE.

JOHN C. TUTTLE, JOHN SMITH, AND MARTIN L. WIENER, OF AKRON, OHIO, AS-

SIGNORS T TI-IE CORPORATION 0F OHIO.

FIRESTONE TIRE AND RUBBER COMPANY, 6OF AKRON, OHIO, A'

TIRE CONSTRUCTION.

application med March 2 1920, seriai No. 362.686.

In the constru-ction of tire casings for pneumatic tires it is customaryto build up the carcass or foundation of the tire of aplurality oflayers or plies of rubberized fabric, the number of layers dependingupon tlie size of the tire. The number of rplies is usually determinedby the cross section, it being the general practice in fabric tires toprovide four plies in a tire of three o r three and one-half inch crosssection and to add a ply for each half inch cross section. rlhus a fourinch tire has five plies, a four and one-half inch tire six plies, andso on. These plies may be of Woven fabric, such as canvas or duck. Onthe outer surface of the carcass built up from layers of fabric issuperposeda cushion strip of rubber, a breaker strip and the rubbertread. The Whole structure so formed is then vulcanized.

Heretofore, it has been the universal custom to use the same Weight offabric in all the plies and to rubberize, or coat and impregnate withrubber, to equal thickness in all the plies. We have found that byincreasing the proportion of rubber contained in the plies, outwardlytoward the tread of the tire, remarkable results have been obtained inwearing qualities. `It has also been found that if the outer ply, orplies, are made of more loosely Woven fabric than the inner plies,-Whichincrease the proportion of rubber-longer life is insured for the tire.

While the description of the specific method of carrying out theinvention is quite detailed, it Will be understood that when theprinciples have been outlined, it is possible to embody the sameinvention here disclosed and claimed in other forms and such forms areintended to be covered hereby.

Fig. l is a cross-section of a tire, which for the sake of deinitenesswill be understood to be a four and one-half inch tire.

Fig. 2 is a very greatly enlarged cross section of a small portion of atire.

Fig. 3 is a plan'of a portion of the' tire, also enlarged, showing aportion of the cushion removed. e

he tire section, as shown, comprises the usual carcass designatedgenerally by the numeral 1, the cushion 2, breaker 3, and tread 4. Inthe lower inner edges of the Renewed July 25, 1924.

tire are embedded the usual beads 5, in the form shown as straight-sidebeads, but may be clincher or any other construction.

The carcass is'cfomposed of a plurality of layers of fabric impregnatedand coated lWith yrubber, this work being done in the usualcalenderingoapparatus. The fabric may be either square Woven fabric,such as shown in the drawings, cord fabric as is used in the manufactureof cord'tires, the cords being spaced in the tire in the mannerillustrated in Figure 2, or any other type of fabric,

In the specific example which we have chosen to illustrate, a carcass isshown comprisinw six layers, the first five layers being composed ofclosely woven fabric and the'` of more loosely Woven last or top layerfabric, and it Will be noted that the .layers increase in thickness asthey approach the tread of tue tire, which increase .is due to a heaviercalendering or coating of the fabric with rubber, but that the last plyof'loosely Woven fabric, While of the same thickness as the oneimmediately below it, contains a larger proportion of rubber.

For the sake of clearness, the first five layers of closely Woven fabricare designated 6 to 10 inclusive, and the outer layer as 11. While We donot Wish to be confined to any dimensions, such as now are to be given vin detail, such proportions and gauges have been tried and found to giveexcellent results. e

Plies numbered 6 to l0 inclusive may be made from the standard 17%c oz.duck at present in use,'while ply numbered 11 may be madeof 12 oz. duck,Which, While of the same thickness, is more loosely Woven, permit-ting agreater amount of rubber to be contained therein. The first and secondpliesand 7 -may be calendered to a gauge of .040 inch, the third andfourth-8 and 9- to a gauge of .045, and the ifth to gauge of .050. Thesixth and last ply may also be calendered to a gauge of .050, but due tothe loose Weave, a greater proportion of rubber is carried in that plythan in any of the preceding plies. i

The cushion layer may be of any desired gauge, it being possible toreduce the thickness of the cushion from that of former tireconstruction without loss of cliiciency to the tire.

We are unable at the present time to give any adequate or extendedinformation as' l. 'A tire construction comprising a cars" cass formedof a plurality of layers of fabric coated and impregnated with rubber,the

thickness of said layers of fabric and rubber increasingoutwardlytowards' the tread of the tire, several of the layers` being of closely-Woven fabric and an outer layer of more loosely Woven fabric, wherebythe amount of rubber Within the several layers is of increased thicknessoutwardly of the tire.

2. A tire construction comprising a carcass formed of a plurality oflayers of textile .elements coated and impregnated with rubber, thethickness of said layers increasing outwardly toward the tread of thetire, the elements of an outer layer being spaced greater distancesapart than those in the inner layers whereby there will be a greateramount of rubber in the outer regions of the vcarcass than in the innerregions thereof.

3. A tire construction comprising a carcass formed of a plurality oflayers of textile elements coat'edand impregnated with rubber, theouter-.layers of said elements adjacent the tread being provided withthicker coatings of rubber than the inner layers thereof and theelements of an outer layer being spaced greater distances apart than theelements of the inner layers whereby there is a greater proportion ofrubber in the outer regions of thecarcassadjacent the tread than thereis in the inner regions thereof.

JOHN C. TUTTLE. JOHN RSMITH. MARTIN L. WIENER

